I took a train from Paddington to Castle Cary back in June, and realised upon arriving that I had forgotten to bring my Young Person's rail card. This was a genuine mistake, and I hold a valid rail card. I was asked to pay for a brand new fare on the spot, which was £100. As I couldn't afford to pay at the time, I was later sent a letter asking me to pay a penalty of £152. My original ticket cost about £23 as it was both an advance fare and reduced further by the rail card. I have sent two letters admitting my mistake and providing evidence of my valid in date rail card, but they've rebuffed my attempts to reason. I understand that it is my responsibility to be able to present it at the time and this was a fault on my part. However, what I don't understand is how not showing my rail card invalidates the 'Advance' part of my ticket. I feel that the penalty is grossly unfair and I am genuinely unable to afford it. I'm being put into the same category as somebody who never purchased a ticket in the first place, which seems absurd. What, if anything, can I do next?